People
We are never so happy or so unhappy as we suppose.
— François de la Rochefoucauld ‧ Maxim 49

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The saying questions how accurately we judge our own happiness and unhappiness. Both can seem more extreme than they are, in the speaker's view. The balanced wording casts doubt on each judgment without singling out either hope or despair.
Context reviewed